A conventional motorised rolling apparatus is described in Australian Patent Specification 522301 which relates to an undercarriage supported by a pair of ground engaging rollers. There was also provided a main frame also having a third ground engaging roller and drive means for driving one of the rollers so as to propel the rolling apparatus in a line of travel along a surface generally normal to the third roller. Coupling means were provided between the undercarriage and the main frame so as to allow pivotal movement of the undercarriage with respect to the main frame about a generally vertical axis. However, the coupling means was such so as to only allow pivotal movement of the undercarriage with respect to the main frame about a horizontal axis parallel with the direction of travel of the rolling apparatus and not about a horizontal axis normal to the direction of travel. In other words in a x-y-z axis frame of reference pivotal movement of the undercarriage with respect to the main frame could occur about the y axis if the y axis coincided with the direction of travel but not about the z-axis. To this end there were provided levelling bolts which were interposed between the undercarriage and main frame which had to be adjusted constantly so as to ensure that the three rollers were oriented in a common horizontal plane. However, it was found in practice that this was relatively time consuming. Also the rolling apparatus of Patent 522301 was prone to produce corrugations in the surface being rolled if the three rollers were not oriented in the same horizontal plane. It was also considered that the apparatus of Patent 522301 was unduly complicated in construction because of the inclusion of the levelling bolts.